Megalochelys

One species of Megalochelys, M. atlas, is the largest known tortoise, with shells of in length having been reported. Popular weight estimates for this taxon have varied greatly with the highest estimates reaching up to in some instances. However, weights based on volumetric displacement of the skeleton suggest a mass of around . M. atlas is thus the largest known tortoise. though the epiplastron (the frontmost-portion of the lower carapace) was forked and very thick. Such forked epiplastra are found in some living tortoises, where they are used for combat and shoving contests between males. The skull of Megalochelys could grow over in length, and had a deep nasal region and a deep and rather short snout, similar to living Aldabra giant tortoises. == Taxonomy ==

The genus Megalochelys was first named in 1837 Hugh Falconer and Proby Cautley based on remains found in the Sivalik Hills of northern India with species Megalochelys sivalensis. However, later in 1844, Falconer and Cautley decided to rename the species Colossochelys atlas and later Geochelone. Today, Colossochelys is regarded as a junior synonym of Megalochelys. The original species name M. sivalensis is regarded as a nomen nudum due to lacking a proper description (though the genus name is valid due to differing ICZN standards on the naming of genera and species) making M. atlas'', which was accompanied by a proper description, the valid name for this species, Megalochelys is the original and valid name for what has been called Colossochelys. It contains three named species with several unnamed taxa. • Megalochelys atlas Falconer and Cautley, 1844 Late Pliocene to Early Pleistocene, India (Sivalik Hills) probable nomen dubium.) Flores, Indonesia == Extinction ==

The genus is suspected to have gone extinct due to the arrival of Homo erectus, due to staggered extinctions on islands coinciding with the arrival of H. erectus in these regions, as well as evidence of exploitation by H. erectus. The genus was largely extinct by the end of the Early Pleistocene, but persisted on Timor into the Middle Pleistocene. == See also ==